Smoke-consuming forced-draft steam-boiler furnace.



A. CTTON.

SMOKE CNSUMHIG FORCED DRAFT STEAM BGHR?. YURNAGE.

APPLIATISN FILED Mi. 26, 1805i n 907,572, Patented Dee. u,

' A. COTTON. SMOKE GONSUMING Forum) DRAFT STEAM BOILBR PURNAUE.

APPLICATION FILED MAR.. 26, 1906.

Patented Dec. 22, 1908.

' H TS-SHEET 2,

am a A. CTTON` 5mm; GONSUMWG PQRGED DRAE-T STEAM Boum PURNAGE.

APPLIOATIN FLI'VD MAE. BEL 15M Patented Dec. 22, i908.

6 SHEETS-SHEET 3 COTTON.

A. SMOKE GONSUMING Femm umm STEAM Boum mamas APPLIATIGN FILED MAR. 26.1906. 907,572, Patented Dec. 22

6 SHEETS -smn'r A. COTTON. SMOKE GONSUMING FORCED DRAFT STEAM BOILEB.FUENAGE.

.IPLIOATIDIEI| FILED 12.26. 1906.

Patented Deo. 22, 1908. 6 SHEETS-SHEET @w Agar/9241;:

| l I 2m J: g@ 5 @E @E C@ (11.101 nur Wig/mwen '6% A. GTTUN. BMKEUONSUMING FORCED DRAFT STEAM DO ILBR PUBNAB. APPLIUATION rum] nn. 2a.190e.

907,572, Patented nec. 22. 1908.

6 SHEETS-SHEET t]4 ami/huwen A wvc/wtz EZ@ 'Mmm' u i" W i; atto; mq?

- evolved whenthe fisc is the line the ,and Fi ALFRE COTTON, 0F NEWARK,NEW JERSEY.

BHOIQE-GONSUMING FORCED-DRAFT BTEAM-BILER FUENAGE.

iro. 907,572.

Specification of Letters Patent.

Patented Dec. 22, 1908.

Application lcd latch 26, 1906. Serial No. 807,982.

To all whom 'it may concern:

Be it known that I, ALFRED COTTON, a sub'ect of the King of GreatBritain, residing at ewark, in the county of Essex and State of NewJersey, have invented certain new and useful 1m rovenients inSmoke-Consumin ForccdraftSteam-BoilerFurnaces, of which the following isa specification, reference eing had therein to the accompanyingdrawings, in which Figure 1 is a perspective view of the fui-4 nace;Fig. 2 a horizontal sectional view on I-II of Fi 3; Fig. 3 a verticalsectional view on the Fine IlI--IH of Fig.,2; Fig. 4 a transversevertical-sectional view on line IV-IV of Fig. 2; Fig. 5 a frontelevation of a portion o the furnace; Fig. 6 a side elevation of thefurnace; Fig. 7 a vertical transverse section on the line VII-VII of F'2; Fig. 8 a .detail view of the steam supp y valve controlled by thefire door; Fig. 9 a vertical sectional view of the -iire door; Fig. r10a vertical sectional view of the fire door on the line X-X of Fig. 9;Fig. 11 a side elevation of the fire door; Fig. 12 a partial plan viewthereof;I Fig. 13 a partial front elevation showing Vthe upper end ofthe fire door; Fig. 14 a vertical sectional view of the controller forthe secondary air; Fig. 1-5 a similar view ofthe controller taken on alane at ri ht angles to the plane offlig. 14; Fig. 16 arp anview of thecontroller; Fig. 17 anenlarged elevation of the fire bricks throughwhich the steam -and air pass into the fire box; Fig. 18 a horizontalsectional view on the line XVIII-XVIII, of Fig. 19; 19 a verticalsectional view on the line Xl '-XIIX of Fig.. 17

One of the many ob ects or this invention is-to rivide a force draffurnace which will cciently burn all descriptions ofsolid fuel, t-whicliis particularly well adapted. to efficiently burn bituminous coal andother smoky fuels withlthe emission of' very little or nosrnoke. l V yAs is well; kndwn, immediately a fresh supply of bituminous coal isthrown upon the fire the distillation of hydrocarbons commences, and ifsmoke-.ia to. be prevented a supply of air must b8 admitted above' or"after the (iro to properly consume these hydrocarbons. Hydnocar ons arealso broken up from time to time through the fire door.

Itis one of the main bects of this inven- *im *ef-smid@ when the firedoor is open for the purpose of either adding a fresh supply of fuel orbreaking up the fire, a supply of air, which may be termed secondaryair, will be delivered above the fire in such manner and in suchcontrolled quantities that the hydrocarbons will be consumed and smokeprevented.

A further object of the invention is to so construct the furnace thatthis secondary air will bev delivered in such manner as to be mostefficient both as to the amount, of air, the len tli of time uring whichthe air is fed to the ire, and as to the direction of the air currents.

There are many other im rtant features of the invention which wil bemore fully hereinafter described and. particularly set forth in theappended claims.

Referring to the various parts by numerals, 1 desi nates the boilerproper which is supported y the walls of the furnace in the usual, or inany ap roved manner; and 2 the grate bars wluch a o may be of anydesired orm. The bridge wall 3 is hollow near its upper end to forni thehorizontal transverse iiue 4, as shown clearly in Figs. 2 and 3. In theside walls of the furnace horizontal lues 5 and 6 are formed, said luesconnecting at their rear ends with the ends of the flue 4 formed in thebridge wall; and inthe front Wall of the furnace is formed a horizontalflue 7 which is connected to the forward end of the flue 5 and extendsabout half way across the front of the furnace, terminating short of thefire door opening, as shown clearly in Ifig. 2. All of these fines' arear ranged a suitable distance above the grate bars, as shown clearl inFigs. 3 and 4, and the walls of all of sai flues arepi'evided withopenings which put said llues into commu-ni- ;cation with the lire boxabove the rate.

The forw half of the inner wal of the flue 6 is rfc ated, and the rearhalf of the inner Waiibf 1 he flue V5` is likewise erforated, sigel: thei penings in one wal 'are diag- 0 y opposie those of an opposite walland directly opposite the solid portion of the wall on tlieppposite sideof the ire box, as shown clearlyc in Fig. 2. The inner wall of the flue7 is perforated and that plortion of the fire box wall of tlm Vtime!!whic is directly opposite flue 71is not perforated, the other ha of saidwellbeing perforated as show n clearly in 2. The object of so locatingthese o n is to produce a circular motion of aiieamt gas over the nrewhen au: is adthe' supply o secondary air is delivered by a l at its uper end and with a larger in et port combustionsecurem withoutinterfering at actuated controller 13 which is connected by mitted intothe ues 4, 5, 6' and 7 when the fire door is open as will be more fullyhereinafter described. It will be readily seen that by this peculiararrangementof the air jet openins the infiowing air from 'oiieset ofjets wi be diverted by the jets from an ad- Joining set of openings, andthat the result will be a rotary movement of the/air over the fire. Therear wall of the bridge wall flue 4 is also perforated to permit air to`ass back into the combustion chamber at t e rear of said wall. At therear of these o enings is arranged an upward and rearward) inclineddeiiector wall 8 against which the air iiowing rearward from the bridgewall flue willimpinge and will be spread and directed upward. At the tipof the divergin wall 8 is a flatcrown wall 9 over which t e gas passes.This crown wall is comparatively narrow and from its rear edge the bed10 of the combustion chamber inclines downward and rearward to the rearwall of the furnace. One s ecial advantage in providing the crown waand'A the downward and rearward inclined part 10 of the combustion bedis to secure a swirling of the gas and air just in the rear of the crownwall. By thus causing eddies in the air at this point it is held backand amore perfect all with the draft of the furnace. Connected t'o thecenter of the bridge wall flue 4, at the bottom thereof, is a flue 11into which projects a blower 12, said blower being located inthe sidewall of the furnace, as shown clearly in' Fi 2 and 7 and through whichsteam Jet, said jet being controlled, when the iire door is o en, bymeans of automatic mechanism w ich is permitted to operate when saiddoor is swungto its open position.

The automatic controlling m ns for the secondary air supply consists othe steam suitable pipes to the steam supply, the jet blowers and thevalves bymeans of which the controller is regulated. The controllerconsists of an upper vertical steam cylinder 14 and a lower watercylinder 15, the two cylinders being connected to lether and incommunication with each ot er as shown clearly in Figs. 14 and 15. Thesteam cylinder is provided with a small inlet ort 16 17 at its ower end.The main steam suppl pipe .18 is connected to the ort 17 throng pipe 19and to the port 16 t rough pipe 20, said pipe 20 being connected to pipe19, as shown clearly lin Fig. 6. In the pipe 19 isprovided a-reglatingvalve 21 and 1n the pipe, 2() is provided a small valve 22. Valve 22,1'is o en slightly so as to permit steam to f slowy leak through pi e 20into the'upper end of the steam cylin er 14 and to therel gradi.allyequalize the ressi: re of steam a mitted to the lower en of said steamcylin der through ipe 19. By means of the valve 21 the supp y of steamto pi e 19 may be regulated, or entirely cut oil s iould occasionrequire. In the cylinder 14 is mounted a piston 23 which is normallynear the bottom of said cylinder but above the ort 17, said piston inits normal position c osing outlet port 24, as shown clearly in Fig. 14.Connected to the piston 23 is a downward eX- tending piston rod 25 whichprojects` into the cylinder 15 and carries at its lower end a piston 26which fits the interior of the water cylinder 15. This piston' is formedwith a port 27 which is closed by a spring pressed valve 28 seatingagainst the under sideof said piston, sai valve opening downward. Theupper and lower ends of this Water c linder are connected by a passage29 which opens into the cylinder near the ends thereof and above andbelow the piston 26. The upper end of this assage 29, where it opensinto the c linder, is controlled by an adjustable need e valve 30.

The water cylinder is supplied withwater from the condensation in thesteam cylinder. When the piston 26 is moved up, as will be hereinafterdescribed, the valve 28 opens downward and ermits the water above thepiston to pass t rough the poitc27 so that the piston-will move upwardrapidly. When the piston is again depressed or rmitted to' return to itsnormal position t e valve 28 closes port 27 andthe water below thepiston will move slo ly, throu h passage 29 to the upper art i) thecyliner above the piston 26. T e speed o f the piston in its downwardmovement ma;T be readily overned by the adjustment of thelneedle va ve'30.

Connected to the port 24 of the steam cylinder 14 is a steam pi e 31 andthis pipe is connected to the steam jet of theblower 12 by means of apipe` 32, and the pipe 20 is connected with valve I 33 by a pipe 34.Pipe 3i is connected at its forward end to a steam jet 35 which isai-ran' ed to deliver steam into the upper end o a blower 36 which ismounted vertically in the top of the fire-door 37. In the pipe 31 justabove the {ire-door is arranged a valve 38. On the fire dooris secured avalve operating arm 39 which carries at its up er end an adjustablestriking-pin 40 which is adapted to engage the stem 41'of the valve 38when the fire door is closed to force the said valve stem inward andopen the valve 38, thereby permitting steam to flow through pipe 31 andjet 35 into the blower 36 when the fire door is closed. The valve 38 isan ordinary selfclosing valve which will automatically return to itsseat when the' fire door is' open and the stiil ing nFm 40 is moved awayfrom the valve stem. 'he p1 rpose of this is to prevent steam Howi'ngthrough the pipe 35 w en the fire door is open.

The v ilve 33 is piovided with alstem- Q2,

.bridge wall and against the deilector wall i to be placed on the fireor to break up the which vtedto be en aged by a ivot'pd arm 43, sai? armbeing nrmally drzwn tbl Award the valve stem 42 by means of a spring 44.The outer freeend of the arm 43 is rovided with an adjustable eye-bolt45 and said eye-bolt ishcnnected` to 'the fire-door by means ofa chain46. From the valve 33 a ipe 47 leads into the ash-pit under the gratears.

The operation lof'the controller for the secondary air'may be brieflydescribed as follows z-In'the normal position of the parts, after yhetire door has been closed for a con- Siders-ole period the piston 23 ofthe controller `rovers the port 24 thereby preyenting steam assing intothe pipe 3l. The ressure oipsteai above and below the piston 23 and in'pipe 24 is equal. When the fire door is opened eitherto permit freshfllel lire, valve 438 will be closed immediate by reason of the arm 39being swung away from said valve. This will revent'steam issuing fromthe jet 35. As t e door swings on its pivot the spring 44 will swing thearm 43 and cause it to force inward the valve stem 42 thereb openingthe4 valve 33 and permitting t e steam to escape from ipe 34 th'ough pie 47 into the ash-pit. "Fhiswill at once ex aust steam from the upperpart of the cylinder 14 above the piston therein, and permit thesteambelow said iston to force it upward. The steam will t en pass throughport 24 into pipe 31 to the steamjet blower 12, thereby Lnjectin steamand airinto the flue l1 and thence t rough fines 4, 5, 6, and 7. Fromthese ues the air and steam will pass into the fire-box above the lireas. previously described. The steam and airwill also pass rearwardlythrough the 8 and thence rearward through the combustion chamber asreviously described. This will continue as llbng as the fire-door isopen and the valve 33 is held in its open position. Should itvbe desiredto open the fire-door at any time without blowing secondary air over thefire as described, it is simplv necessary to hold the'arm 43 away fromthe valve stem 42'while the door is open. The chain 46will permit thisto he done.

When the lire door is closed valve 38 will 'be'at once opened throughth(` arm 39, and striking-pin 40, and steam will issue from the jet 35and air and steam'will pass through the. blower 36 into the fire-doorand from thence into the fire-box above the lire, as will be more fullyhereinafter described. (ln i closing the firefdoor the chain 46 willswing arm 43 away-f|om the valve stem 42 and i permit valve 33 toautomatic-ally close, said ialw' being an ordinary self-closing vulve.As soon as this valve i.; closed the pressure in the pipe 34 and in thctop ol the steam F cylinder 14 will be gradually raised byreason of theleakage of steam through the valve 22. This gradual raising of the steampressure in the upper part o the cyhnder 14` will gradually depress thepiston 23, by reason of the wei ht of the lar e piston 26 connected tothe ower end of t e stem 25. This downward movement `of the iston 23will be governed, as hereinbefore escribed` by the speed of the watermovin upward through the passage29. Steamwil continue to flow throughipe 31 to the blowers 36 and 12 until piston 3 is moved to the limit ofits downward travel and covers port 24. AAs soon 'as it reaches thispointl steam will be cut oil from the blowers 12 and 36 thereby stoppingthe supply of secondary air. The main supplly of air is fed into theash-pit through t e main blower 48 which is su plied with steam throughthe main supp y pipe 49 connected to the ipe 18. .The ash. p'it isclosed in any suitab e manner to maintain an air pressure below therate. Pipe 19 is connected to the blower 12 y means of a pipe 50 inwhich is arranged a Valve 51.'

By this means the blowers 12 and 48 may be supplied with steam ifdesired independently of the controller 13.` This -valve 5l is normallykept closed.

The fire-door is preferably hollow'as shown in Figs. 9 and 10 and itsinner side 52 is perforated for the passage of steam and air intov thefire-box above the grate. Near the, vertical edges of the inner plate 52of the door and near its upper ed e is formed a depression, one wall vofwhich is at an angle to the adjacent wall of the {ire-door opening.Perforatio'ns 55 are formed in this angularbr disposed wall pf thisdepression so that steam and airl passing through said openings willimping on the adjacent wall of the fire door opening. as shown clearlyin Figs. 9 and 10. The oblect oi' this is to bring said air into directContact with the highl heated lane surface whereby said air wil beheater and the consumption of smoke and hydrocarbons assisted.

The perforations through the inner side ol' the fire door are arrangedinhorizontal rows and between every other row, on the ire side of thedoor, is arranged an inward extending horizontal rib 52, as shownclearly in Figs. 9 and IU. The walls ol' the` openings adjoininr each ofsaid ribs are inclined towards saii rib. as shown clearly in Fig. 10, sothat air passing through said openings will impinge upon the. sideofsaid rib. The object of this is 1o have the air heated and deflectedby those ribs.

rlo secure the best distribution of air around the {ire-box throu rh theopenings from the flues 4, 5, 6. and Lil form said openings by meansof-fifre bricks 56 of culiar shape. These bricks are shown in r etail inFigs. l?, 18 and 19. They are double the height or thickness of theordinary fire brick,

-course, where it is under-cut, and the outer face, that is, that facewhich is not ex osed -to the fire, is downwardl and outwar 1y j n- 10,

clined. In each end of t e brick is formed a roovel which is at an angleto the horizontal lbwer ed e of the brick, and inclinesdownward aufinward toward the lire' box. The

grooves in two adjoining bricks form down ward and inward inclinedcylindrical passages through which the ail' passes -iiito the fire-boxfrom the flue. The air is directed by these passages on to the lanesurfaces 62,

and is-by them heated an( deflected.

It will be noted that the outlet ends oi the passages formed by thegroove 6l are within the face of the lire-bini wall and .that the openinto angular recesses formed in said wal the bottom of-said recessesbeing horizontal as shown clearly in Figs. 17 and 19. By thisconstruction the ends of the passages formed by the grooves 61 will beprotected and said opening will`-not be clicked by the molten slag andhet cinders and clinkers from the fire-box. The brick 56 is not easilybroken as its cross-sectional area is greatest in the middle of itslength. j

Openings in the furnace wall around the fire ox as ordinarilyconstructed are liable to total or partial closure by a kind of moltenslar or clinker which slowly runs down the wa holes. With myconstruction such clinker will run d'own the edges 58 of the brick tothe.

corners 59 and from there will pass down the face of the furna%e wall.Should any elinker accumulate at the corners 59 by reason of saidclinher being cooled by the inflowing air, it can be easily removed,when the furnace is not in o eration, without lia ility ofdamage to theire bricks. The infl wing air is not only heated or deflected by thesurfaces 62 but will berspread by them also. The result of this is thatthere is practically a thin sheet or film of air passing into the lirebox from these openings.

The air flowing rearward through the bridge wall will be so spread bythe deflect or wall that a thin 'film or sheet of air will pass over thecrown of said defi ector wall into the combustion chamber. I t isalsointended that the ribs on the fire door shall spread the nflowingjets of airjn'like manner." It will thus be seen that the air will bequickly heated and fed into the fire box and combustion chamber in thinsheets or films so that it will be thoroughly mixed with the heatedgases. j

In Fig. 15 a spring 75 is shown within the water cylinder above thepiston 2th and is cooled by the air'issuing from the purpose of this` isto assist in restoring said piston to its normal osition when the steampressure in the cylin er 14 is equalized above and below the piston 23therein.

From the fore oing it will be readily seen that I provide aurnace havingmany novel features and many advantages. The peculiar method of causingthe inflowi air jets to be given a rotary motion over t e fire Iconsider novel and of great importance. The method of controlling the jsipply of steam and air, or what I term secon ary air, is both novel andefficient.

It will be noted that the fire door is connected to the valve opcratinarm 43 b means oi' a chain andthat t e arm 43v is moved by aspring. Theobject of this is to avoid a rigid connection between the [iredoor andthe valve operating arm` The firedocr may be thrown o en with an degreeof violence without in t ie least a Vacting the valve and without anydanger of in'uring or deranging it. By means of the a justable eye-bolt45 the pro er adjustment may be obtained to secure t 'e proper movementof the arm 43. I also consider it of great importance to'so deliver thesecondary air into the fire-box that it will impinge upon a planesurface and be'by said surface heated and deflected and spread. The airpassin into the fire-box from the flues 4, 5, 6, and 7 is heated bycontact with the surface 62; that which passes into the fire-box throughthe fire-door is heated by contact with the Walls of the fire-dooropening and with the ribs 52"; and that assing rearward through thebridge wall is ieatcd and deflected by conf tact with the deflector wall8. A

Ihave found that when steam is injected directly inte the fire-box,either alone or inducing secondary air, thc ei'l'ect is often to..agrlomerate the carbon articles in sootfl: has which are not so visibleas smoke, but which are more objectionable, and the general result isnot so efficient as when the steam and air are thoroughly mixed beforebeing injected into the furnaee-chamben It will beseen thatthoroughmixture of the steam and air is elle lcd in in llues before it reachesthe discharge ori ces. Further, with my arrangement of llues it is onlynecessary to use two nozzles-one for each blower. In some enses only oneof these blowers mayV bc necessary with one nozzle, though multiple-jetblowers may be used. With strani-jets which blow directly into thefurnace it is generally necessary to have a large number of nozzleswhich either use much steam or are of small bore and choke easily. Alsothey are usually necessarily placed in inaccessible positions. Anyexcessive quantity of steam injected into the furnace chambernecessarily reduces the teinperature of the ases, and it is thereforead- The visable that the lowers used for this purpose be highlyefficient so that the minimum of steam will be used. This is anotherreason why I prefer to use a blower hor blowers to discharge air intothe passaes or flues as described, for in this way the lower may moreeasily be made of correct desiin and may be placed in such a position asto e very easy of access.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. A furnace provided with a fire box, a rate therein, means fordeliverin air to the re-box above the grate, means or controlling thedelivery of said air, said controlling means consistingbof a steamcylinder having an outlet port etween its ends, a piston therein, asteam supply pipe connected to said -c linder near its ends, means tonor; mally iold said piston at one end of its stroke when thc steampressure therein is erualizcdon both sides of said piston, the out etport from said cylinder being closed by the piston in its normalposit-ion, a steam jet blower connected to the outlet from said steameylinder, and means whereby the opening of the lire door will permit thesteam to be exhausted from one end of the steam cylinder whereby thepiston therein will move toward said exhaustedend and uncover the outletport to permit steam toflow to the jet blower, and means whereby whenthe lire door is closed the steam pressure on both sides of the pistonin the steam c rlinder will be slowly equalized and the supply of steamto the jet blower interrupted after a predetrmined time.

2. Acontroller for a steam jet blower comprising a steam cylinder, awater cylinder elow the steam cylinder, a piston in the steam cylinder,la piston in the water cylinder, a plstonstem connecting said pistons, avalve 1n the water piston, a steam supply connected tofthe steamcylinder above and below the piston therein, an outlet from saidcylinder normally covered by said piston, means to exhaust the upper endof the steam cylinder, and means topyrmit the pressure in the steamcylinder to equalize to return the piston therein to its normalposition.

3. A controller for a steam jet blower comrising a steam cylinder, awater cylinder beow the steamleylinder, a piston in the steam cylinder,a piston in' tln.l water cylinder, a iston-stem connect-ing saidpistons, a valve 1n the water pistou, a steam supply connected to thesteam cylinder above and below the i piston therein, an outlet from saidcylinder 'nornially covered by said piston, means to exhaust the upperend of the steam cylinder, means to permit the pressure in the steam clinder to equalize to return the piston t erein to its normal position,and means to regulate the movement of the water in the Water cylinderfrom one side of the water piston to the other to govern the speed ofthe'o piston in the steam cylinder.

4. A furnace rovided with a fire box, a

rate therein, a ire door, steam jet blowers or supplying seconda r airover the tire, a steam actuated contro er for regulating the supply ofsteam to the blowers, an exhaust pi e connected to said steamcontroller, said ex iaustv ipe bein normally closed as ringactuate eviceor opening said ex aust pipe, a` {lexible device connected to saidspring actuated device and to the tire door whereby said device is freeto operate when the door is open.

5. A furnace provided with a lire box,A a lglrate therein, means fordeliveri U air to the rebox above the grate, means or controlling thedelivery of said air, said controlling means consisting of a steamcylinder, a piston therein, a steam supply pipe connected to saidcylinder near its ends, means to normally hold said piston at one end ofitsstroke when the'steam ressurc therein isf'equalized on both sides osaid piston, the outlet port from said cylinder being closed by thepiston in its normal position, a steam jet blower connected to theoutlet from said steam cylinder, and means for exhausting the steam fromone end of said steam cylinder whereby the piston therein will movetoward said ex. baust end and uncover the outlet port and permit steamto flow to the blower.

6. A furnace provided with a steam jet blower for delivering air andsteam into the fire box, means for controlling the delivery of steam tosaid blower, said means consisting of a steam cylinder, a iston therein,a steam supply ipe connecter to said cylinder near the em s thereof,means to normally hold said piston at one'end ol its stroke when thesteam pressure is equalizcd on both sides thereof, the steam outlet fromsaid qrlinder being closed by the iston in its normal position. meansconnecting the steam `et blower to the outlet from the steam cylinr er,means operated by the o ening of the lire door for exhausting steam romone end of said steam cylinder, whereby the piston therein will be movedtowards said exhaust end and thereby uncover the outlet port and permitsteam to flow to the blower. Y'

7. A furnace provided with abre box and a fire door, a steam jet. blowerfor delivering air anil steam into the fire box, a steam jet blower fordelivering air and steam into the fire box through the fire door, meansfor controlling the delivery of steam to said blowers, said meansconsisting of a .steam cylinder, a piston therein, a steam suppl) pipeconnected to said cylinder umulluends thereof, vmeans to normally holdlsind piston at one end of its stroke when the steam pressure isIequalized ou bolli sides thereof, the steam outlet from said cylindersurA A door-to being closed by the piston in its normal position, meansconnecting the two steam jet blowers to the outlet from the steam clin-i der, means Yoperated by the opening'o the fire doo'r forehaustingsteam from one end of said' steam cylinder to permit steam toi flow tothe blower connected to the fire box, means operated by the closing ofthe lire rmit steam to flow from said cylinder to t efire door blower,means operated by they closing of the fire door to close the exhaustfrom the steam cylinder, and means to permit the steam to equalize onboth sides of the pistonin the steam cylinder when. the exhaust fromsaid cylinder is closed. l

8. A furnace provided with a steam jet blower for delivering air andsteam into 4the fire box, means for controlling the delivery of steam tosaid blower, said moans consisting of a steam cylinder, a pistontherein, a steam sup'ply pipe connected to said cylinder near the endsthereof, means to normally.v` hold said piston at one end of itsstrokewhenl the steam pressure is qualized on both sides thereof, thesteam outlet from said cylinder being closed by the piston in its normalposition, mea s connecting the steam et blower to the out et from thesteam cylinder, means operated by the opening of the fire door forexhausting steam rom one end of said steam cylinder, whereby the pistontherein will be moved towards'said exhaust end and thereby uncover theoutlet port and ermit steam to flow to the blower, meaps w icreby theclosing of the fire door .will cut off thc exhaust from the steamcylinder, and means to e ualize the steam pressure on both sides o thepiston in the steam cylinder when the exaust therefrom is cut off.

9. A furnace provided with a steam jet blower for delivering air andsteam into thc fire box, means for controlling the delivery "of steam tosaid blower, said means consisting of a steam cylinder and a watercylinder, a piston in the steam cylinder, a piston in the watercylinder, a stem connecting said pistons, a steam supply pipe connectedto the steam cylinder near the ends thereof, the steam outlet from saidcylinder being closed by said piston in its normal position, means topermit the water on one side of the piston in the water cylinder topassto the other side thereof when the pistons are moved, a steam jetblower connected to the outlet from the steam cylinder, and means oerated by the opening of the fire door for exhausting steam from one endof the steam cylinder to thereby uncover the outlet port from saidcylinder.

10. A furnace provided with a steam jet blower for delivering air andsteam into the fire box, a fire door, a' steam jet blower for deliveringair and steam into the fire box through said door, means for controllingthe delivery of steam to said blowers, said means consisting of a steamcylinder, a piston therein, a steam supply pipe connected to saidcylinder near the ends thereof, the steam outlet from said cylinderbeing closed by the 'piston in its normal position, means connecting thesteam jet blowers to the outlet from .the steam c linder, means o eratedby the opening of t e fire door for ex austing steam from one end ofsaid steam cylinder, means operated by the fire door to prevent steamassing to the fire door jet blower while the e door is open, and meansoperated by the closing of the fire door to' permit steam to pass to thefire door jet blower and to close the exhaust from the. steam cylinder,and means whereby when said exhaust is closed the pressure on both sidesof the piston in the steam cylinder will be equalized.

11. A furnace comprising a fire box, a steam jet blower connected to theire box, a fire door, a steam jet blower in communication with the iireb'ox through said door, means operated by the opening of the fire `doorto supply steam to the fire box jet blower while said door is o en,means operated by the closing of the re door to permit steam to How tothe fire door net blower,

means o ieratedb the closing of l to stop t e iiow o steam to theblowers a prei getermined time after the closing of said oor.

12. A furnace comprising a ire box,a pair of steam jet blowers, a steamactuated controller governing the supply of steam to said blowers, afire door, means whereby u on the opening of said fire door 'steam willsuppied to one f said blowers and will be cut ofi' from the otherblower, means whereb upon the closing of said fire door steam wi l beadmitted to the other blower, and means whereby steam will beautomatically cut oill from both of said blowers a predetermined timeafter the :losing of said door.

13. A furnace rovidecl with a fire box, a steam jet blower or deliveringsteam and air into said fire box, a fire door, a steam actuatedcontroller 4coiit'ainin a balanced steam actuated piston, means w erebythe 4opening of the fire door will exhaust steam from one side of saidbalanced piston and -permit the piston to be moved towards saidexhausted side, means connecting the steam jet blower with thecontroller whereby steam will be supplied to the blower when thebalanced piston has been moved from its normal position b thel openingof the iirc door, means where y the ressurc on the balancedV piston ofthe contro ler will be equalized when the re door is closed, and meansconnected to said balanced piston to permit it to be slowly returned toits normal position to cut oil' the steam supply to the steam jetblower.

14. A controller for a steam jet blower comprising a steam cylinder, awater cylinder below the steam cylinder, a piston in the t ie fire door;

steam cylinder, a piston in the water cylinder, a plsten stem connectingsaid pistons, a valve 1n the water piston, a steam supply Conner-,ted tothe steam cylinder near the ends thereof, an outlet from said cylindernormally covered by said piston, a steam jet blower connected to theoutlet from said eylnder, a flre door, means operated by the epenin; oftbe re door to exhaust steam from t le upper part of the steam cylinder,said means cutting off said exhaust when the re door is elosed, andmeans to permit the pressure in the steam cylinder to equalize to returnthe iston therem to its normal position when tle re door is closed.

l5. A forced-draft apparatus comprising a pair of steam jet` blowers, asteam actuated controller governing the su )ply of steam to saidblowers, means adapted to be operated by the opening of a furnace redoor to supply steam to one of said blowers and to Apre\'ent steamreaching the other blower, l

and means adapted to be operated by the elosng of the re door to openthe steam supl Yly to the other blower, and means Wherefy steam will beautomatically cnt ,ei from both of said blowers a predetermined time'after the elosing of the fre door.

16. A furnace comprising a fire bex, a steam blower, a steam aetuatedoontroller governing a supplyr of steam to said blower, a re door, meansWllerelnr upon the opening of said re door an exhaust -valve will be oened and the steam controller will be move( to plaee the steam supply ineem-,

ALFRED COTTON.

Witnesses 1 WM. R. DAVIS, E. I. CAUQHLAN.

